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Monday

Top Attractions of Chicago Sears Tower

At the time the Sears tower was constructed in 1974, it was the world's tallest building, eclipsing New York's twin-towered World Trade Center
by 25 meters (83 ft). It would keep the title of tallest building in
the world until the Petronas twin towers in Kuala Lumpur, Malaysia were
constructed in 1997.

Sears Tower

Ledges on the Sears Tower (Willis Tower)

Sears Tower seen from the Shedd Aquarium

The Tallest

There was much discussion on whether the Petronas Towers are actually taller
than the Sears Tower as the height of the antennas on the Petronas Towers are
included in the total height, while the height of the antennas are not included
in the height calculation of the Sears Tower as they are not considered an actual
part of the building.

With the construction of the 508 meters tall Taipei 101 in 2004 this
discussion became irrelevant. However, when in November 2013 New York's One WTC
was officially declared taller than the Sears Tower - grabbing the
coveted title of the tallest building in the US, the issue was brought
up once again: one WTC's rather pathetic spire was included in the
calculation of its height, so that even though the Sears Tower's roof is
a substantial 25 meters (83 feet) higher than One WTC's, the latter is now officially 99 meters (325 ft) taller.

Anyhow, the Sears tower is still the tallest Chicago skyscraper, exceeding the
height of the number two, the Trump International Hotel and Tower by 27 meters (89 ft) and the Aon Center by 96 meters (315 ft).

The Structure

Sears Tower at night

The building consists of nine framed tubes, which are actually nine skyscrapers
on themselves taken together into one building. Originally, the plan included
no less than fifteen tubes, but when the planned hotel was

taken out of the project,
only nine tubes were used in the final designs. The nine tubes all reach forty-nine
stories. At that point, two tubes end. The other rise up to the sixty-fifth
floor. From the sixty-sixth to the ninetieth floor, the tower has the shape
of a crucifix. Two tubes, creating a rectangular, reach the full height of 442
meters (1451ft).

Wind Load

The result is an interesting tower, which looks different from all
angles. The construction, designed by Fazlur Kahn (1929-82), has other
advantages : the construction with separate tubes provides lateral
strengths to withstand the
strong Chicago wind loads, as each tube only needs to take a part of
the pressure.

Observation Deck

The Sears Tower's observation deck - known as the
skydeck - is one of Chicago's most popular attractions. At 1,353 ft or
412 m, it's Chicago's

highest observatory, besting the John Hancock Center's by 323 ft (98m).
The most spectacular attraction at the skydeck is 'the ledge', a glass
balcony extending 4.3 ft where you can look straight down. It will make
most people feel uneasy at first but the balconies offer spectacular
views over Wacker Drive and the Chicago River.

Willis Tower

The tower was named after Sears, Roebuck and Co.,
an American chain of Department Stores which was headquartered here.
Sears sold the building in 1993 after moving to the suburbs. The
building's name was left unchanged until Juli 16, 2009, when it was
renamed Willis Tower for one of the skyscraper's tenants, a British
insurance firm. The move was met with local opposition however, and some
even started online petitions to protest the name change.